Senior Liberal Democrat peer Lord Rennard will not apologise to female activists who accused him of sexual harassment, despite an investigation by a leading lawyer concluding he should say sorry.

Disciplinary proceedings against the party's former chief executive were dropped after a QC concluded there was a less than 50% chance the allegations could be proved beyond reasonable doubt, although there was broadly credible evidence of "behaviour which violated the personal space and autonomy of the complainants".

Lord Rennard's legal representative, fellow Lib Dem peer Lord Carlile, said there was no reason for an apology and criticised Alistair Webster QC, who was appointed by the party to investigate the allegations, for making that recommendation.

Party leader Nick Clegg has ruled Lord Rennard out of playing a role in his 2015 election campaign, but the peer has rejoined the Lib Dem group in the House of Lords and will return to his duties as an elected member of a key policy committee.

The end of the disciplinary process, which followed a decision by the Metropolitan Police not to press criminal charges, was met with dismay by some of the women who accused Lord Rennard.

Alison Smith told BBC Radio 4's Today programme: "Unfortunately it's a bit of a fudge that doesn't really seem to please anybody and it raises more questions than it answers."

She said "hell would freeze over" before Lord Rennard apologised but "the first step to rehabilitation is to admit that you have done something wrong".

Lord Carlile said Mr Webster had concluded that the allegations could not have been proven on either the criminal standard of "beyond reasonable doubt" or the lower civil test of proof, and Lord Rennard had always denied any wrongdoing.

Lord Carlile told Today that Mr Webster examined four statements with complaints relating to Lord Rennard and "about 100 which refuted those complaints".

Asked if Lord Rennard would apologise, Lord Carlile said: "No, because there's no reason why he should because he has denied these allegations which have not been tried. Alistair Webster should not have said that."

He said neither he nor Lord Rennard had seen the Webster report in full, which was a "terrible example of secret justice".

Deputy Prime Minister Mr Clegg said: "People in positions of authority should never subject anyone to behaviour which is offensive or inappropriate. It is as simple as that.

"I want everyone to be treated with respect in the Liberal Democrats. That is why it is right that Chris Rennard has been asked in the report to apologise, to reflect on his behaviour and why he won't be playing any role in my general election plans for the campaign in 2015."

Mr Clegg told LBC 97.3 radio that Lord Rennard should now "do the decent thing" and apologise to the women who complained.

"He should apologise," said the Lib Dem leader. "I think it is a matter of very real regret - to put it mildly - that, so far at least, he hasn't chosen to apologise.

"I want him above all this morning to do the decent thing, as asked for by the QC who has looked at this very meticulously, very fairly and very reasonably and said 'You owe them an apology'."

Mr Clegg said the Webster Report showed that there was more work to be done on improving the party's internal procedures, and that he had asked party president Tim Farron to conduct a review of whether the Lib Dems should continue to require that an allegation meets the criminal burden of proof - that it is true "beyond reasonable doubt" - before taking disciplinary action.

The Deputy Prime Minister said it was "obvious" that the women involved "were subjected to behaviour that caused them distress".

"It is frustrating for me, when I think the women have been wronged and let down by the party, they are owed an apology and they are not being given the apology they deserve," he said.

But asked whether he would expel Lord Rennard from the party, Mr Clegg said he had to follow "due process". If someone refused to apologise, "I can't frogmarch them to do so, but I nonetheless appeal to their common decency", he said.

Prime Minister David Cameron's official spokesman declined to comment on the Rennard case.

But he told a regular Westminster media briefing: "I think it is right that people in every walk of life show the respect to others that every single person deserves."

End Violence Against Women Coalition said the party's response was "disappointing" at a time when a string of high-profile sex abuses cases had highlighted the issue.

"The urgent need for policy and action to tackle and prevent abuse of women and girls could not be more obvious.

"But on the same day what do we find at the very top of one of our main political parties?

"'Confusion' about what constitutes abuse and about the law, excuses for unacceptable behaviour, and a continuing lack of policy and protection for women when sexual harassment occurs.

"This is a failure of leadership. How does this look to women workers, voters and political party activists, and to the majority of men who deplore such behaviour?

"It is extremely disappointing."

Susan Gaszczak, one of the Liberal Democrat party members who brought allegations against Lord Rennard, told Channel 4 News that he"owes" her an apology.

Waiving her right to anonymity, she said: "I guess I will put on a brave face and continue to be strong and to get through this. It is not nice. He owes me an apology and that is the minimum that he owes me."

She claimed it would be "extremely difficult" to work alongside Lord Rennard and she may cut up her membership card.

She said: "I have been a member of this party for 25 years, why should I resign?

"I may well cut it up. I am going to sleep on it and make a very rational decision before I cut it up but I really would like that apology and that is the minimum I would expect."

She said that Mr Clegg had called her last night and apologised "as he did to all the women".

Ms Gaszczak told Channel 4 News: " He reassured me that he wants to change the rules so that this does not happen again - but he needs to be firmer. We should not be calling for the women's resignations, we should be calling for Rennard's resignation and that should be the membership as well as the MPs."

Claiming that the rules are "weak", she said that someone at the top of the party needs to "man up" and helps ensure this sort of situation cannot happen again.